# Search results

1. ### I CMA (Cylindrical Mirror Analyzer)

I'm supposed to be working with a CMA (Cylindrical Mirror Analyzer), but I'm more interested in the physics behind it. This is the instrument in question that we are looking to get: http://www.rbdinstruments.com/products/micro-cma.html We want it to look at different eV levels of different...
2. ### Arduino Line Follower Robot

I'm looking to build an Arduino that is capable of following a line depending on a colored strip on the ground, either black or white. I think I might use a LDR, but not quite sure where to even start to be honest. My office is having an Arduino contest, and I just want the Arduino to carry...
3. ### Other Mathematical Methods in the Physical Sciences (alternative?)

Is there any alternative books that teach you how to just do the problems rather than emphasizing why, and is there any books that emphasize why in an easier format? Something like a "mathematical methods for dummies" book? This is the book I'm referring to (...
4. ### Mass of half ball

Homework Statement If the density of the half-ball x ^2 + y ^2 + z ^2 ≤ 4 ; z ≥ 0 is given by δ(x, y, z) = ( x^ 2 + y^ 2 + z ^2)^(1/2) find its mass. Homework Equations ∫∫F⋅ds ∫∫FoΦ(u,v)||Tu,Tv||dudv ∫∫FoΦ(u,v)⋅(Tu,Tv)dudv The Attempt at a Solution For the last problem I was asked to find...
5. ### I Normalizing Constant 3D Infinite Well

For time independent Schrodinger's equation in 3-D Where Enx,ny,nz=(nx/Lx2+ny/Ly2+nz/Lz2)(π2ħ2/2m and Ψnx,ny,nz=Asin(nxπx/Lx)sin(nyπy/Ly)sin(nzπz/Lz) How do I normalize A to get (2/L)^3/2? I don't think I understand how to normalize constants.
6. ### What inspired you?

What inspired you to choose the major you are currently doing/did. Was there a certain topic that excited you as a child that lead you to do what you did in school? Perhaps you read about particle-wave duality, and that was enough to spark your interest, or quantum mechanics, or cell division or...
7. ### Diretional Derivative

Having a melt down as I have done this problem twice now and my exam is tomorrow and I can't seem to figure it out anymore.... ugh. 1. Homework Statement The depth of a lake at the point on the surface with coordinates (x, y ) is given by D(x, y ) = 100−4x 2 −y 2 . a) If a boat at the point...
8. ### Find a normal vector to a graph

How do you find a normal vector of a function at a point, such as f(x,y)= ax^y+yx^y^x+b at (X_o,Y_o) where a and b are just arbitrary constants, and the function is an arbitrary function. So I guess, what is the general steps you take to find the normal? I thought it had to do with the...
9. ### Delta T in Calorimetry always positive?

For part number 5, it says to make sure that each ΔT is positive. Why is this? Couldn't it be a negative? Or does it have to be positive since if it wasn't you would be getting heat going in the wrong direction? Like the one substance would be gaining instead of losing the heat? Which would...
10. ### Average Speed for Maxwell's Distribution of Molecular Speed

Using the Maxwell-Boltzmann equation above, there is an example in my book (Giancoli 4th edition p. 481) where they use this to find the average velocity. I understand that it would just be the sum of all the speeds of the molecules divided by the number of molecules. But then I'm having...
11. ### Greenhouse effect affected by Earths Gravity?

Hey, so I was thinking how the atmosphere is held close to earth due to gravity and realized that if certain molecules have a certain amount of kinetic energy, they are bound to leave the atmosphere correct? I mean there is an escape velocity that these molecules must need and I'm sure molecules...
12. ### Ideal Gas Law in "alternate" universe

Homework Statement Assume that in an alternate universe, the laws of physics are very different from ours and that "ideal" gases behave as follows: (i) At constant temperature, pressure is inversely proportional to the square of the volume. (ii) At constant pressure, the volume varies directly...
13. ### Arduino and Chromebook (Plug-in)

Hey for a while I thought that I would have to always lug around my huge HP laptop in order to code for my Arduino... seeing as my slim, sleek, light weight chrome book has an OS that revolves around apps rather than programs. But then found out about a thing called Codebender (...
14. ### Benefits of Carburetor over Fuel Injection?

What are the benefits of carburetors over fuel injection methods in engines? I have started working on motorcycles and have noticed that even modern motorcycles are carb'ed rather than fuel inject. Is it because of the cost of adding a computer? Or is there something else to it? I know that...
15. ### What is a ghost?

The website on the main page on the lower right will tell you the staff that is on, and some of the members, along with that it tells you how many guests and how many "ghosts" are these just random computers that have left Physics Forums open in another tab? (Something I have been guilty of many...
16. ### What does f|S mean?

I am in Calculus 3, and I do not under stand what it means when they ask to find the relative extrema of f|S? The problem is usually something like f:R^n=>R, (x,y,z) |=> (some function) , S= {(x,y) | x e R} What does f|s mean? How does this relate to Lagrange multipliers? The book does not...
17. ### How many of you ride Motorcycles/Scooters?

Hey, I've been lurking in the forums for a while and would still consider myself pretty new to the forums. I just want to know how many of you guys ride a motorcycle? What is your favorite style? How many of you know too much kinematics in order to ride a motorcycle safely? :DD Also how many...
18. ### Not the brightest, but I try!

I love tutoring physics and mathematics at the high school level. But when it comes to some of the questions here that are much more conceptual and are college level math and physics problems, I am hesitant to answer, since I might be wrong. But I still want to offer an input and try to help...
19. ### Classical First Book in physics course?

I was just curious on what was everyone's first Physics book, or what was their first encounter with Physics? My first academic physics book that was not calculus based was my junior year of high school and was Conceptual Physics: The High School Physics Program by Paul G. Hewitt, and then...
20. ### Strained Eye

Homework Statement This is not really a homework problem but I wanted to figure out how to derive the equation for a strained eye which is $$M= (N/f)$$ where N is the object distance from the normal near point, and f is the focal length of a magnifying glass. But then, this is for a relaxed...
21. ### Solving index of refraction for Total Internal Reflection

Homework Statement Homework Equations Snell's Law n1sin(theta_1)=n2sin(theta_2) Total Internal Refraction: sin(theta_c)=(n_2/n_1) lambda_n=lambda_n The Attempt at a Solution So I drew the triangle and this is what I got, and well here is just a picture so far of what I have. [/B] I've...
22. ### Using Arduino as a Logic Switch

I want to supply some LED's and a motor from an outside source of electricity (i.e. a battery pack, wall outlet, batteries in series, etc.) and want to use the Arduino to be able to "switch" on and off these sources so that I am able to control long strands of LED's with the Arduino (for like a...